The overall goal of this project is to determine the extent to which morphologic, physiologic and immunologic alterations after vasectomy are reversed by a subsequent vasovasostomy, and to correlate specific alterations with post-vasovasostomy infertility. During the current grant period, we studied Lewis rats which received either a bilateral vasectomy and a later vasovasostomy, a vasectomy alone, or sham operations. Some vasectomy-induced alterations were not reversed by a subsequent vasovasostomy. The first aim of the proposed work is to determine the nature and sequence of the initial alterations after vasectomy in the Lewis rat and to determine whether the lesions and infertility are reversible by vasovasostomy, provided it is performed early enough. The second aim is to define autoantigens and the role of antisperm antibodies in development of testicular alterations after vasectomy in Lewis rats. Comparisons, with respect to autoantigens recognized, will be made between sera from animals showing elevated antisperm antibodies with and without testicular alterations, and between sera obtained before and after vasovasostomy. The third aim is to determine whether the reversal of reproductive tract alterations, antisperm antibody levels, and fertility after vasovasostomy in Lewis rats can be modified by treatment with immunosuppressive drugs (glucocorticoids and cyclosporin). The fourth aim is to determine the extent to which alterations after vasectomy are reversed by vasovasostomy in Sprague-Dawley rats, and, most importantly, to determine the basis for the differences in fertility after vasovasostomy which we have observed in preliminary studies on this strain. Young adult male rats will be subjected to bilateral extrascrotal vasectomy and, at a later time, a microsurgical vasovasostomy will be performed. A second group of animals will receive a vasectomy but no vasovasostomy, and a third group will receive sham operations. The animals will be studied at several intervals after the operations. Methods include light and electron microscopy, measurement of intraluminal hydrostatic pressure by micropuncture, probing of the blood-testis barrier with tracers and freeze-fracture, intratesticular testosterone determinations, measurement of the resistance of the vas deferens to fluid flow, determination of serum antisperm antibody levels with an ELISA, and fertility testing. Post-vasectomy autoantigens will be studied by gel electrophoresis, western blotting, and vectorial labeling techniques.